Cloud server and method for controlling cloud server thereof

A cloud server comprising a plurality of security modules, the cloud server further comprising:

• a communicator comprising a circuit;
• a storage device that can be accessed by the plurality of security modules;
• and
• at least one processor configured to:
• based on receiving a request signal of preparation for data transmission and identification information of a user of an external device from the external device through the communicator, acquire security data corresponding to the identification information through one security module among the plurality of security modules, and control the communicator to transmit the security data to the external device,
• store the acquired security data in the storage device so that the plurality of security modules can share the security data, and
• based on receiving data to be stored in the cloud server and security data from the external device through the communicator, authenticate the user of the external device based on the received security data and the security data stored in the storage device by using at least one security module among the plurality of security modules, and store the data to be stored in the cloud server in the storage device.